FROMLIST: [PATCH v6 05/12] arm: vdso: Add support for CLOCK_MONOTONIC_RAW
(cherry pick from url https://patchwork.kernel.org/patch/10052099/) Take an effort to recode the arm64 vdso code from assembler to C previously submitted by Andrew Pinski <apinski@cavium.com>, rework it for use in both arm and arm64, overlapping any optimizations for each architecture. But instead of landing it in arm64, land the result into lib/vdso and unify both implementations to simplify future maintenance. Add a case for CLOCK_MONOTONIC_RAW to match up with support that is available in arm64's vdso. Signed-off-by: Mark Salyzyn <salyzyn@android.com> Cc: James Morse <james.morse@arm.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Dmitry Safonov <dsafonov@virtuozzo.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Laura Abbott <labbott@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Andy Gross <andy.gross@linaro.org> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Andrew Pinski <apinski@cavium.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Bug: 63737556 Bug: 20045882 Change-Id: If9c09d131e236ba4a483dbc122e6b876f471df72
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3 changed files with 58 additions and 0 deletions
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@ -34,6 +34,11 @@ typedef u32 vdso_wtm_clock_nsec_t;
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typedef u32 vdso_xtime_clock_sec_t;
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#endif
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#ifndef _VDSO_RAW_TIME_SEC_T
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#define _VDSO_RAW_TIME_SEC_T
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typedef u32 vdso_raw_time_sec_t;
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#endif
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/* Try to be cache-friendly on systems that don't implement the
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* generic timer: fit the unconditionally updated fields in the first
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* 32 bytes.
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@ -58,6 +63,12 @@ struct vdso_data {
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u64 xtime_clock_snsec; /* CLOCK_REALTIME sub-ns base */
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u32 tz_minuteswest; /* timezone info for gettimeofday(2) */
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u32 tz_dsttime;
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/* Raw clocksource multipler */
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u32 cs_raw_mult;
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/* Raw time */
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vdso_raw_time_sec_t raw_time_sec;
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u32 raw_time_nsec;
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};
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union vdso_data_store {
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@ -319,9 +319,12 @@ void update_vsyscall(struct timekeeper *tk)
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if (!vdso_data->use_syscall) {
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vdso_data->cs_cycle_last = tk->tkr_mono.cycle_last;
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vdso_data->raw_time_sec = tk->raw_sec;
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vdso_data->raw_time_nsec = tk->tkr_raw.xtime_nsec;
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vdso_data->xtime_clock_sec = tk->xtime_sec;
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vdso_data->xtime_clock_snsec = tk->tkr_mono.xtime_nsec;
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vdso_data->cs_mono_mult = tk->tkr_mono.mult;
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vdso_data->cs_raw_mult = tk->tkr_raw.mult;
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/* tkr_mono.shift == tkr_raw.shift */
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vdso_data->cs_shift = tk->tkr_mono.shift;
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vdso_data->cs_mask = tk->tkr_mono.mask;
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@ -194,6 +194,40 @@ static notrace int do_monotonic(const struct vdso_data *vd, struct timespec *ts)
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return 0;
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}
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static notrace int do_monotonic_raw(const struct vdso_data *vd,
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struct timespec *ts)
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{
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u32 seq, mult, shift;
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u64 nsec, cycle_last;
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u64 mask;
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vdso_raw_time_sec_t sec;
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do {
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seq = vdso_read_begin(vd);
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if (vd->use_syscall)
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return -1;
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cycle_last = vd->cs_cycle_last;
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mult = vd->cs_raw_mult;
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shift = vd->cs_shift;
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mask = vd->cs_mask;
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sec = vd->raw_time_sec;
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nsec = vd->raw_time_nsec;
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} while (unlikely(vdso_read_retry(vd, seq)));
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nsec += get_clock_shifted_nsec(cycle_last, mult, mask);
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nsec >>= shift;
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/* open coding timespec_add_ns to save a ts->tv_nsec = 0 */
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ts->tv_sec = sec + __iter_div_u64_rem(nsec, NSEC_PER_SEC, &nsec);
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ts->tv_nsec = nsec;
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return 0;
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}
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#else /* CONFIG_ARM_ARCH_TIMER */
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static notrace int do_realtime(const struct vdso_data *vd, struct timespec *ts)
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@ -206,6 +240,12 @@ static notrace int do_monotonic(const struct vdso_data *vd, struct timespec *ts)
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return -1;
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}
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static notrace int do_monotonic_raw(const struct vdso_data *vd,
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struct timespec *ts)
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{
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return -1;
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}
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#endif /* CONFIG_ARM_ARCH_TIMER */
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notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
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@ -227,6 +267,10 @@ notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
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if (do_monotonic(vd, ts))
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goto fallback;
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break;
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case CLOCK_MONOTONIC_RAW:
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if (do_monotonic_raw(vd, ts))
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goto fallback;
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break;
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default:
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goto fallback;
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}
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